Some Blue Foam Questions

Discussion in 'HO Scale Model Trains' started by rudyy, Dec 17, 2006.

  1. rudyy

    rudyy New Member

    1) Is 1 inch the most approparate thickness I should get?
    2) What kind of tool I should use to cut the foam? Can I use a paper knife?
    3) Can I use the white glue for wood to clue the foam to the bench?

    Many Thanks,

  2. bigsteel

    bigsteel Call me Mr.Tinkertrain

    hi rudy if you are making mountains i find that 2 inch foam is a little more forgigiving and is easier to shape, but if it is for under layment just use the one inch, it wont make a difference but if you use 2 in you can cut out divets in the foam to make small hill detail or lakes and ponds.
    for cutting the foam i use a hot wire foam cutter to shape my foam you can move it around better than a knife to make more intricate cuts.
    for gluing i use liquid is stronger than white glue yet fairly cheap(although white glue is good for gluing card board strips for scenery)
  3. Amrap1

    Amrap1 Member


    I used 1 1/2 because I may want to "cut out" for a river or creek or ????. I would think it would depend on what you want to do at "ground level".

    I cut my sheets to fit the bench with a hacksaw blade, clamping a board down as a straight edge and guide. It does make alittle bit of a mess, which is why I cut it outside. If you're using 3/4 foam, a utility knife works well.

    From what I have read, Elmer's white glue works well. I've seen people pour the glue on the wood and spread it out pretty evenly over the whole area. An old train guy told me that I should just put down a line around the edges so that if something changes the foam can be pulled up with less foam sticking to the wood. Sanding that off will be easier when you're ready to reglue new foam.

  4. rudyy

    rudyy New Member

    I just have the workbench setup, and I am looking for the blue foam for the base. I guess 1 inch or 1.5 inch should be fine then. The 2" one may appear to be too thick for the base, but it will be good for building hills and slopes.

    Does Lowes have the hot wire foam cutter?

  5. Amrap1

    Amrap1 Member

    I bought mine a train show. Great for carving thick foam for scenery. I have never looked at Lowes or Home Depot for one.

  6. rfmicro

    rfmicro Member

    You may also find the hot wire foam cutter at Woodland Scenics where I got mine. There are probably other vendors that are cheaper. The hot wire foam cutter is probably the best for initial cuts on larger foam. The use of a wire brush also achoeves good results to acieve a smoother form. For triming and finer modifications I find using a xacto knife work very well especially if you desire to form rock formations prior to priming and painting.

  7. 60103

    60103 Pooh Bah

    I use hot wire, X-acto knives. and a box-cutter. I don't use any blade with teeth as it makes dust. I find that the box-cutter tends to wander in 2" foam, but that's the only blade long enough to go through.
    WS hot wire has an additional accessory with an angle attachment, but mine tends to lose its setting.
    I like to start with a sharp blade to go through the surface, then make a lot more cuts.
    I've found I can make straight sloping cuts, e.g. tapered platform ends, but mounting straight stripwood on both sides of the foam and running the hot wire along it. Watch out for irregular bits on the wood (splinters) and go with the grain. Also watch out for pins or toothpicks that have been used to hold layers of foams together.
    Hot wire does not like to cut through paint.
  8. sidetracked

    sidetracked Member

  9. Jim Krause

    Jim Krause Active Member

    You can also use a hacksaw blade, utility knife or keyhole saw if you're in a budgeting mode. Actually the thickness of the foam can vary depending on what broken sheets you can get from the lumber yard or building supply the cheapest. I find that liquid nails works well to glue the layers together. I even found a broken sheet of 2 inch foam along the highway. Worked as well as the bought stuff.
  10. TrainNut

    TrainNut Ditat Deus

    I use 1".
    I use a Woodland Scenics hot wire cutter.
    Elmers. Sparingly. I've used wood glue and found that it does seem to dry quicker and may be a little bit stronger however, your not building a house here :D & it's all in compression so strength is not a real issue (not for me anyways).
  11. Santa Fe Jack

    Santa Fe Jack Member

    It depends. If your foam base is fully supported, then 1" will be fine, though as other point out, you may want it thicker in places wo that you can delved down into it. I needed a 6ft x 10ft base, and so made one with a laminate of three 1" thick layers to make a 3" base. In places where I wanted to go deeper, I simply glued more sheets on underneath.

    I started by using a hot knife, but the fumes! Jeez - they are nasty! The fumes are actually quite toxic -- full of dioxins just like burning plastic. In the end, I found that I had more control and no fumes with a simple hacksaw blade mounted in a hole-saw type hacksaw blade handle -- it holds it from just one end. The only down side is the fine foam mess, but that cleans up fairly easily.

    I agree that Liquid Nails is the best -- they even make a version for foamboard, but I don't know if it is really that different. It will NOT dry quickly, however, as the foam does not "bearthe" or allow exposure to air. I have found taht I have to clamp it up and leave it for two days or more before it has stuck.
  12. MasonJar

    MasonJar It's not rocket surgery

    The thickness depends on what is underneath. If you are laminating it to a full plywood deck, then 1" is fine if you don't need features deeper than about 7 scale feet (if you do there are other ways to achieve this than thicker foam, but I digress).

    If you are putting the foam over "open grid" benchwork, then I would recommend 2" foam instead. It is strong enough to support itself and a good deal of scenery weight, provided your grid is no more than 24" on centre.

    A glue that many of the local modular guys ( are now using is the polyurethane type (Gorilla glue is one brand). It cures whne exposed to moisture, rather than air, so will "dry" right to the inside of the joint. The problem with white or yellow glue is that it dries around the edge, effectively sealing still wet glue inside. It may dry eventually, but that's a long time to wait...! ;)

    As for cutting it, long, thin knives seem to be the tool of choice for shaping. Deboning knives can be honed to razor sharpness fairly easily. Cutting the slab of foam to fit your benchwork can be done on the table saw, but take care not to melt it by either forcing it or going too slow...

  13. Santa Fe Jack

    Santa Fe Jack Member

    I would not advise using the table saw. Just do what foam board installers do - score the sheet with a utility knife, and break it along the cut line.

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